Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 54: Si/Ge
HL 54.15: Vortrag
Freitag, 29. Februar 2008, 14:15–14:30, EW 202
Diffusion and defect reactions between donors, carbon and vacancies in germanium — •Hartmut Bracht1, Sergej Brotzmann1, John Lundsgaard Hansen2, and Arne Nylandsted Larsen2 — 1Institute of Materials Physics, University of Münster, Germany — 2Department of Physics and Astronomy, University of Aarhus, Denmark
The diffusion of self-atoms and n-type dopants such as phosphorus (P), arsenic (As), and antimony (Sb) was studied by means of isotopically controlled germanium multilayer structures doped with carbon. The diffusion profiles reveal an aggregation of the dopants within the carbon-doped layers and a retarded penetration depth compared to dopant diffusion in high purity natural Ge. Dopant aggregation and diffusion retardation is strongest for Sb and similar for P and As. In addition, the shape of the dopant profiles changes for high dopant concentrations. Accurate modeling of the simultaneous self- and dopant diffusion is achieved on the basis of the vacancy mechanism and additional reactions that take into account the formation of neutral carbon-vacancy-dopant and neutral dopant-vacancy complexes. The stability of these complexes is compared to recent theoretical calculations. The overall consistency between the experimental and theoretical results support the stabilization of donor-vacancy complexes in Ge by the presence of carbon and the dopant deactivation via the formation of dopant-vacancy complexes.